Web applications can be considered as a specific variant of client–server software where the client software is downloaded to the client machine when visiting the relevant web page, using standard procedures such as HTTP.Client web software updates may happen each time the web page is visited.HTML5 also enriched the semantic content of documents.
However, every significant change to the web page required a round trip back to the server to refresh the entire page.
In 1995, Netscape introduced a client-side scripting language called Java Script allowing programmers to add some dynamic elements to the user interface that ran on the client side.
The general distinction between a dynamic web page of any kind and a "web application" is unclear.
Web sites most likely to be referred to as "web applications" are those which have similar functionality to a desktop software application, or to a mobile app.
Through Java, Java Script, DHTML, Flash, Silverlight and other technologies, application-specific methods such as drawing on the screen, playing audio, and access to the keyboard and mouse are all possible.
Many services have worked to combine all of these into a more familiar interface that adopts the appearance of an operating system.Single-page frameworks like Sencha Touch and Angular JS might be used to speed development of such a web app for a mobile platform.In earlier computing models like client–server, the processing load for the application was shared between code on the server and code installed on each client locally.General purpose techniques such as drag and drop are also supported by these technologies.Web developers often use client-side scripting to add functionality, especially to create an interactive experience that does not require page reloading.In other words, an application had its own pre-compiled client program which served as its user interface and had to be separately installed on each user's personal computer.